This invention relates to a monolithic integrated circuit device having input circuitry protection integral therewith. More particularly it relates to a monolithic integrated circuit chip that includes an input resistor capable of absorbing surges of hundreds of volts.
It is known that input portions of integrated circuits may require protection from voltage surges. It is not unusual to want to include electrical components to provide such protection. If the voltage surges are fairly low, one can easily include planar-type components on the chip to absorb them. However, if the voltage surges are quite high, in excess of 50 volts, such components are not adequate.
It is not practical to include a high power zener diode on an integrated circuit chip. As a result, high voltage surge protection is conventionally not provided on the chip itself. It is normally provided in the connected external circuitry. If such protection could be provided on the chip itself, with components compatible with regular integrated circuit processing, one could increase reliability and decrease cost. An ancillary benefit, of course, is reduced size, weight and complexity of overall circuitry required.
No monolithic integrated circuit is currently available that has integral input circuitry protection capable of handling hundreds of volts. It is particularly desirable to provide such protection in automotive electrical systems, where transients of several hundreds volts are known to occur. A monolithic integrated circuit having integral input circuit protection capable of absorbing such transients may even permit such circuits to be more readily included in wiring harnesses, harness connectors and the like. This could simplify overall circuitry, lower its cost, and increase its reliability.